[PATCH RFC 07/10] tty: serial: Add Cortina Systems CS75xx UART driver

[Jason Li]

> -----Original Message-----
> From: Fil Dunsky <filipp.dunsky at gmail.com>
> Sent: Thursday, October 1, 2026 11:26 AM
> To: Jason Li <jason.li at cortina-access.com>
> Cc: Arnd Bergmann <arnd at arndb.de>; Linus Walleij <linusw at kernel.org>;
> Krzysztof Kozlowski <krzk at kernel.org>; Rob Herring <robh at kernel.org>;
> Krzysztof Kozlowski <krzk+dt at kernel.org>; Conor Dooley
> <conor+dt at kernel.org>; Greg Kroah-Hartman <gregkh at linuxfoundation.org>;
> Jiri Slaby <jirislaby at kernel.org>; Russell King <linux at armlinux.org.uk>;
> Alexandre Belloni <alexandre.belloni at bootlin.com>; Drew Fustini
> <fustini at kernel.org>; Lorenzo Pieralisi <lpieralisi at kernel.org>;
> linux-arm-kernel at lists.infradead.org; devicetree at vger.kernel.org;
> linux-kernel at vger.kernel.org; linux-serial at vger.kernel.org
> Subject: RE: [PATCH RFC 07/10] tty: serial: Add Cortina Systems CS75xx UART
> driver
> 
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> On Thu, Oct 01, 2026 at 03:17:28AM +0000, Jason Li wrote:
> > Yes, they are actually same HW logic. But the brand name of CSxxxx is
> > owned by Marvell instead of Cortina-Access now.
> > Will there any legal issue if unify them as one driver?
> 
> Thanks for confirming that it is the same logic.
> 
> I am not a lawyer, but I do not see a problem here. The part numbers only
> show up as compatible strings, Kconfig help text and comments that say which
> hardware the code runs on, and the kernel does that for chips of companies
> that were bought or split up all the time. The driver itself is GPL code; your
> additions would be under the GPL as well, with your own copyright line.
> Nothing in it uses a trademark to name the product.
> 
> The plan for v2 is a neutral name: drivers/tty/serial/cortina-uart.c,
> SERIAL_CORTINA, port type "CORTINA", and a binding with one compatible per
> SoC ("cortina,cs7542-uart" for mine, a "cortina-access,..." one for yours). If
> Cortina Access would rather have the CA parts described differently in the help
> text or the binding title, tell me what wording you prefer and I will use it.
> 
> Thanks,
> Fil
Thanks for clarifying.
We agree with the approach of using a single UART driver since the CS75xx and CA series share the same UART hardware implementation.
For the Device Tree compatible strings, we would prefer using the "cortina-access" vendor prefix for the CA SoCs (e.g. "cortina-access,<soc>-uart").
We do not have concerns with using a neutral driver name such as cortina-uart. However, for DT bindings and related documentation describing the CA devices, we would prefer the wording "Cortina Access" to distinguish them from the legacy Cortina/Marvell branded devices.

Thanks,
Jason